CVE-2018-20187
MEDIUMEPSS 72th pctlDescription
A side-channel issue was discovered in Botan before 2.9.0. An attacker capable of precisely measuring the time taken for ECC key generation may be able to derive information about the high bits of the secret key, as the function to derive the public point from the secret scalar uses an unblinded Montgomery ladder whose loop iteration count depends on the bitlength of the secret. This issue affects only key generation, not ECDSA signatures or ECDH key agreement.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Exploit Intelligence
Elevated risk: more likely to be exploited than 72% of all known CVEs.
References
Related Vulnerabilities
Other CWE-320 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2015-0936 | Critical | 9.8 | 78% | - | - |
| CVE-2018-0732 | High | 7.5 | 49% | - | Fix |
| CVE-2015-0839 | High | 8.1 | 6.3% | - | Fix |
| CVE-2018-0124 | Critical | 9.8 | 5.1% | - | Fix |
| CVE-2016-9963 | Medium | 5.9 | 3.1% | - | Fix |
| CVE-2016-2217 | Medium | 5.3 | 2.5% | - | Fix |
Common questions
How do I fix CVE-2018-20187?
Upgrade botan on debian 11 to 2.9.0-2 or later.
Is CVE-2018-20187 being actively exploited?
Not that we know of. CVE-2018-20187 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 1.5% is the estimated probability that it will be exploited in the next 30 days. That is higher than 72% of all scored CVEs.
How severe is CVE-2018-20187?
CVE-2018-20187 has a CVSS v3 base score of 5.9, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2018-20187 affect?
Published advisories record a fix for botan (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.